In your event's left navigation menu, locate Setup and then select Event Website. To add a block, under Available Blocks locate which one you want to add to your website, and then click on the '+' icon.

Editing a website block can be done by clicking on the little cog icon of that block, and then making relevant updates. After this cog has been clicked a settings menu will open up and you will be able to change anything you want with that particular block (except the actual text displayed in the block).

Unlike other options such as the section title and background color of the text block which are edited in the settings menu, the text is edited in the preview of the block. The preview is located on the right-hand side and the changes in the default text are made simply by clicking into it. Even the Cover block, which has additional options in the settings menu, is edited in the same way as a text block when it comes to text.

Under "Added Blocks", locate the block you want to remove and then click on the trash can icon next to it and confirm that you want to delete the block.

If your event is in published mode, you will have to republish it in order for the changes to go live.